In fruit flies, intestinal stem-cell regeneration fluctuates
with the time of day
Cirdacian rhythms keep time for all living things, from
regulating when plants open their flowers to foiling people when they try to
beat jet lag. Day-night cycles are controlled through ancient biological
mechanisms, evolutionarily speaking, so in essence, a human has the same
internal clock as a fly does.
These circadian clocks govern daily rhythms through genes
that synchronize molecular pathways that promote or repress protein production,
influencing a multitude of body functions. Even before waking, for example, our
clock-driven metabolism turns on enzymes and transporters that prepare our
bodies to eat and digest food.